High noise level is a common and a necessary evil in any industrial environment wherein powerful machinery is utilized. This problem is most acute in applications where high pressure gases are created or handled and in those situations in which internal combustion engines are used to supply motive power. The sound emanating from such equipment is coming increasingly under the regulation of local and national environmental agencies and laws. Such regulation may be applied not only to those sounds deemed to be hazardous to nearby personnel, but also to those sound and noise levels merely perceived as annoying to nearby residents or bystanders.
The impact of such regulation as well as the prior art may be seen alongside major highways in the form of sound fences erected between the highway and a nearby population center. These prior art fences reduce the level of the sound perceived outside of the highway area by providing a complete vertical barrier to the flow of sound and air, at least near ground level, between the highway area and the nearby residences.
The use of prior art barriers, however, is unsuitable in those situations wherein air breathing machinery is the source of the undesirable sound. Air breathing machinery should be taken to include internal combustion engines, which must ingest a quantity of fresh air for the burning of liquid or solid fuels, heat exchange equipment which relies upon a flow of fresh air to which heat must be transferred, mass transfer devices which exchange volatile matter with incoming air, or other processes or equipment of the like. The prior art sound fence extends from ground level to a suitable height providing a complete block to airflow both into and away from the shielded machinery. This blockage can result in undesirable recycling of spent air to the intake of the air breathing machinery or process.
There is therefore a need for a sound suppression system particularly adapted for use with noisy, air breathing machinery.